Especially since, as I understand it, Terran is a hard race to play at the C-ranks range.

I still play Brood War occasionally because I've always loved the game and always will, but I don't play very much anymore, not enough to get a meaningful ranking. That D+ rank dates back from when I was playing more regularly around 2009-2010. Part of the problem is Battle.net 1.0's matchmaking system, after getting used to the automated ladder, finding games in Brood War is a real chore.